1. Field of the Invention
The present invention relates to a density-adjusting device for adjusting the density of image data for an original read by a scanner or the like, and to an image-reading device employing the density-adjusting device.
2. Description of Related Art
There is a technology used in copiers that is well known in the art for reading an original image and forming a copy of the image on a recording paper (hereinafter referred to as a “copied image”) at an appropriate density. This technology involves setting reproduction characteristics based on the type of the scanned original and performing correction on the scanned image data using the set reproduction characteristics.
For example, a copying device disclosed in U.S. Pat. No. 6,222,640B1 defines reproduction characteristics having a first inflection point (first shoulder point) at the border between a black region and a halftone region and a second inflection point (second shoulder point) on the border between a white region and a halftone region. The copying device of this publication sets one set of reproduction characteristics for binary images, such as texts, and sets another set of reproduction characteristics for multilevel images, such as photographs. The copying device allows an operator to further adjust the first and second inflection points of the reproduction characteristics.